I work at a major transfer station for a power company. The building I work in is basically one big Faraday Cage. I have a cordless 2.4 GHz phone that works in most places inside the building, however, the second I step outside into the switch yard, it's kaput. No signal to the base station. What I need is the capability to communicate to the base station, receive phone calls, and be able to dial certain critical numbers related to the site regardless of my location on the premises. Is there a portable/cordless phone that can do this?